Drill bit



June 9, 1959 s NDV 2,890,021

DRILL BIT Filed Oct. 29, 1956 20.55274. sax owe 24 IN V EN TOR.

United States Patent D LL BIT Rp rt L- Sfl d g Wh ie Calif a g o t ThorPower Tool Company, Aurora, 111., a corporation of Delaware i i Am ifipn O tobe 2 56 Serial No- $51 48 4 Claims. (Cl. 255-64) The presentinvention relates to drill bits in general and particularly to drillbits especially designed for percussive dr l n i r relatively high-speedpenetration of solid material such as rock and concrete is todaypossible by the use of drills using a rota y drilling action andpercussive drilling action or a combination of both. In each type ofdrilling the actual cutting of the material is accomplished by a drillthe working end of which is called a drill bit and which usuallyincludes one or more relatively hard abrasionresisting cutting elementswhich grind and chip the material to be removed. As the material ischipped cut away it must be removed from the hole being drilled, and thespeed of drilling and the success of the operation are dependent uponthe successful removal of the displaced material to prevent its becomingimpacted in the end of the hole. Use has been made of fluid, both airand water, flowing down through the drill rod or steel to the cuttingend and then back around the drill in the hole carrying the materialwith it. Fluid so directed, however, loses velocity as it reaches theWorking face so that the scouring and cleaning action is minimized.Adlifionally, the size of the return passage in the hole around thedrill is much greater than that of the fluidfeeding passage through thedrill, resulting in a relatively sluggish flow of fluid from the holewhich produces slow and sometimes ineffective chip displacement.

' The drill bit constructed in accordance with the present invention isparticularly designed for a drilling operation in which the cleaningfluid is drawn by suction down and into the hole being bored and theninto the working end of the drill bit to be concentrated at a few smallports at the working face. This gives to the cleaning fluid a high-speedscouring action at the face itself, the; arrangement of the face of thedrill bit and the sides thereof being so designed that this scouringaction is increased to a maximum. The foreign material entrained in thefluid. stream is displaced longitudinally through the drill steel fromthe bit and carried to the exterior where it can be separated from thefluid by any suitable means or exhausted to the ambient if that bepermissible.

With an appreciation of the problems present in the field to which theypresent invention relates, it is an objeet to'provide a new and improveddrill or drill bit inwhich the chip-clearing and scouring action of thecleaning fluid is of maximum effectiveness with the drill connected to asource of suction.

Another object of the invention is to provide a new and improved drillbit in which air can be drawn by suction through the bit and around thedrilling face at maximum velocity for maximum chip cleaningeffectiveness.

Another object of the invention is to provide a new andimproved drillbit particularly adapted for percussive drilling with suction in whichthe drill bit body i so constructed and designed as to accomplishmaximum chip removal by the available suction.

these other more specific objects, will appear upon reading thefollowing specification and claims, and upon Patented June 9, 1959considering in connection therewith the attached drawing to rvhich theyrelate.

Referring .again to the drawing in which a preferred embodiment .of theinvention is disclosed:

Figure 1 illustrates a drill bit constructed in accordance with thepresent invention positioned at the end of a drill steel and in a holebeing drilled;

Figure 2 is a longitudinal section through the construction as shown inFigure 1 also being a section upon the line 22 of Figure 3 Figure 3. isan end view looking in the directions of the arrows upon the line 3-3.of Figure 2; and

Figure 4 is a longitudinal section upon the line 4-4 of Figure 3..

Referring again to the drawing, the drill bit construction in accordancewith the present invention is indicated generally by the referencecharacter 10 and is seen to be attached at the outer end of a drillsteel 11 and positioned within a hole H in rock or concrete, forexample, in which it is drilling. The drill steel 11 may be connectedto. any suitable power-actuated drill, either of the rotary orpercussive reciprocating type and preferably the latter. Drill steel 11is provided with a longitudinally-extending bore or passage 12 and atits outer or lower end is tapered at. 1.3. to enable it to. make afriction-locking fit with the drill bit 10. The length of the steel 11may vary. In the conventional use of such units they are connectedinsectiens, intermediate sections being coupled to one another bysuitable means which seal them together. The operat-ion of Such drillsand the interconnection of such drill steels are disclosed in applicantsco-pending applications Serial No. 636,311 and Serial No. 618,749 (nowabandoned), respectively.

Drill bit 10. compnses a body 15 formed of metal which is exteriorlyconical for its entire length at surface 14 which is provided with flats16 in chordal planes parallel to, the longitudinal axis. As is seen mostclearly in Figure 3, the. lower Working end or face of the drills ismultisiderl with spaced arcs lying on the surface of the cone comprisingthe principal shape of the bit body separated bgthe, flats 16..

Drill body 15 is provided interiorly at one end with a conical seat 19sized to receive and seat the tapered end 13 of the drill steel 11. Therelationship is such that when Seated the end ofthe steel is spaced fromthe bottom of the. seat leaving a chamber 21 which opens directly intothe longitudinal bore. 12 extended through the steel.

Portsor passages 22 extend between the chamber 21 and the working face17 of the drill body, the outer ends of the ports in the Working facebeing in substantial tangently to the. fiat 16 in each instance. Thisrelationship is shown most clearly in Figures 2 and 3.

The Working face 17 is provided with transverselyextending diametricgrooves or slots 24 adapted to re ceive and seat cutting elements. Theseelements are indicated by the reference characters 26 and 27, 26 beingseen to extend the. entire width of the cutting face while elements: arepositioned upon its opposite sides. Each of; the. elements is providedwith a cutting edge which extends the greatest distance. from the planeof working face 1 7, all of the cutting edges lying in substantiallythe. same, plane. The retention of the cutting elements in their seats24 may be accomplished in any suitable manner as. by brazing, welding,etc. These elements in a preferred form are made of tungsten carbide orothersuitable abrasion-resisting material.

In the Operation of a tool constructed in accordance with the inventionthe. drill steel and bit are connected tea drill and operated in themanner disclosed in applicants s -s nding application Serial No.636,311. Thedrill stee], is, reciprocated at high frequency and with itthe drill bit 10. Suction at the drill proper is made available at theport 22 in the drill bit through the chem-- ber 21 which connectsthrough the longitudinal bore 12 to the suction source. I

The high-speed reciprocation of the drill bit in the hole H causes thecutting elements 26'and 27 to chip the rock or concrete and thepresence'of suction causes the air to be drawn down the hole H andaround the drill steel and the drill bit. The bit 10 at 'its workingface is of maximum diameter and its conical surface 14 at that faceclosely approaches the Wall of the enclosing hole H. The flats 16,however, provide arcuately spaced channels through which the larger partof the air travels.

The suction is available directly at the ends of the ports 22 and theair rushing through the channels provided by flats 16 sharply reversesits direction as it rounds the face of the bit to provide a scouringaction which removes foreign material from the bottom of the hole andconveys it to the ports 22 from which it makes its way through thechamber 21 into the bore 22 to be exhausted at the drill proper into asuitable dirt separator or into the ambient atmosphere. The entrainedair in the passages 22, chamber 21 and bore 12 travels to the source ofsuction at a velocity which is much higher than would be the case if itwere traveling in the hole around the drill. As a result, the chips andforeign material are effectively exhausted. The pick-up action at theworking face is also improved. The channels formed by the flats 16 withthe cooperation of the wall of the encircling hole H direct the air topockets formed by the included angle between cutting elements 26 and 27in cooperation with the working face 17 and the adjacent end of the holeH. A port 22 opens into each of these pockets right at the end of theflat 16, as described. The result is that the flow of air into each portis largely air from the adjacent channel with resulting increasedconcentration of air flow velocities at the lower ends of the flats 16.

While the particular device herein shown and disclosed in detail isfully capable of attaining the objects and providing the advantageshereinbefore stated, it is to be understood that it is merelyillustrative of the presently preferred embodiments of the invention andthat no limitations are intended to the details of construction ordesign herein shown other than as defined in the appended claims.

I claim:

1. A percussion rock bit adapted to be operated with suction applied tothe central bore thereof comprising a solid metal body exteriorlyconical except for circumferentially spaced flats which lie in planesparallel to the axis of said body and which provide air channels withsaid body positioned within a hole being drilled, transversely-extendedcutting elements in the cutting face of said body the cutting edges ofwhich extend radially between the lateral edges of adjacent one of saidflats, said body being formed interiorly with an axial drill steel seatspaced from said cutting face and communicating with passages whichdiverge outwardly from said seat and opening at their outer ends throughflat surfaces substantially normal to the bit axis and between cuttingelements, and means whereby suction may be applied interiorly of saiddrill body at said seat with said body positioned within a closelysurrounding hole being drilled so that air will be drawn exteriorlyalong said body largely through said air channels formed by said flatswith the adjacent walls of the surrounding hole to ends of said passagesand will reverse its direction of travel to enter said passages and indoing so perform a scouring action which picks up and removes cuttingsfrom the end of the hole being drifled adjacent said cutting faces.

2. A percussion rock bit adapted to be operated with suction applied tothe central bore thereof comprising a solid metal body having a flat endnormal to the bit axis and exteriorly conical except forcircumferentially spaced flats which lie in planes parallel to the axisof said body and which provide air channels with said body positionedWithin a hole being drilled, transverselyextended cutting elements insaid fiat cutting end of said body the cutting edges of which'extendradially between said flats, said body being formed interiorly with adrill steel socket having ports which diverge from the bottom of saidsocket toward said flat cutting end and terminate therein in eachinstance in substantial tangency to one of said flats and betweencutting elements, whereby upon suction being applied interiorly of saiddrill body at said seat with said body positioned within a closelysurrounding hole being drilled the suction in said body will be madeavailable at a point immediately adjacent the ends of said air channelsto obtain maximum velocity of air flow at said ends and maximum scouringand grindingsdisplacement action.

3. A percussion rock bit adapted to be operated with suction applied tothe central bore thereof comprising a solid metal body having a flat endand exteriorly conical except for circumferentially spaced flats whichlie in planes parallel to the major axis of said body and which provideair channels with said body positioned within a hole being drilled,radially extending cutting element seats in the cutting face of saidbody, cutting elements secured in seats each formed with a cutting edgelying in a plane forward of said flat cutting end, said flats beingpositioned in each instance in the angle between adjacent cuttingelements, said body being formed interiorly with a drill steel seat opento its end spaced from said cutting face and with passages which divergeoutwardly from said seat with their opposite ends terminating in saidflat cutting end in immediate adjacency to a flat, whereby upon contactof said cutting element with the end of a hole being drilled eachpassage and adjacent channel opens into a separate pocket formed by thecutting face and the cutting elements with the adjacent end of the holebeing drilled to insure maximum effectiveness of the suction availablein each passage to draw air directly from the adjacent channel.

4. A percussive type rock bit adapted to be operated with suctionapplied to internal passage means extending longitudinally thereof toremove cuttings, said bit having a generally circular body having asubstantially flat end lying normal to the bit axis, a plurality ofcutting elements mounted radially of said flat end, said body beinggenerally conical in shape with its larger diameter portion adjacentsaid flat end, said body also having flats along the side thereofopening through said flat end at points between the adjacent ends ofsaid cutting elements, said body having an axial socket seating the endof a hollow drill steel shank, and suction air passages extendingbetween the inner end of said socket and the fiat end of said body atpoints closely spaced to the merger of said flats with the flat end ofsaid bit, where by suction pressure applied to said socket and to saidpassages is effective to draw air past said flats and into the outerends of said passages at high velocity at points closely spaced from thebottom of the bore being drilled, and whereby the flat end of said bitcooperates with said cutting elements in disintegrating cuttings to asize readily removed by suction air flow.

References Cited in the file of this patent UNITED STATES PATENTS2,103,359 Graham Dec. 28, 1937 2,124,609 Dickenson July 26, 19382,602,641 Wade July 8, 1952 2,733,943 Nater Feb. 7, 1956 FOREIGN PATENTS136,988 Australia Apr. 18, 1950 919,402 Germany Oct. 21, 1954

